1. Field of the Invention
This invention relates to the field of magnetic recording and playback, and in particular to apparatus including a magnetic head supported for radial movement in relation to a flexible magnetic storage disk.
2. Description Relative to the Prior Art
In the course of manufacture, it is necessary to control six position parameters, or degrees of freedom, of a magnetic head in relation to a disk drive in which it is mounted for movement. These six parameters, with reference to FIG. 1, are: the penetration of the head into the plane of a rotating disk supported upon a disk drive spindle; the radial tracking orientation of the head with respect to a true radial path P intersecting the drive spindle; the azimuth rotation of the head about an axis normal to the plane of the disk at the head location; the attack angle rotation of the head about an axis through the head and coincident with the radial path; the tilt angle rotation of the head about an axis through the head and tangent to the radial path; and the lateral location for assuring accurate head indexing between tracks.
Though useful with a variety of head structures and disk drives, the present invention is disclosed in connection with the type of head structure shown in U.S. Pat. No. 4,620,250, in which the head protrudes through an elongated opening in a flat, circumferential stabilizer surrounding the head. As shown in this patent, penetration and the attack angle are set by the way in which the head is glued into the stabilizer (penetration) and fastened to the head transport (attack angle). It is further known, as shown in U.S. Pat. No. 4,456,938, to set the remaining (or all) degrees of freedom in a specialized fixture as the head is loosely positioned in a head carriage. A space allowing slight movement of the head is filled with inactive glue or cement that is activated, for example, by injection of a catalyst or by ultraviolet light, after the head's position has been properly adjusted.
Such a technique as practiced by the '938 patent may successfully set the various parameters, but only through a relatively complex procedure involving elaborate apparatus. For instance, in that disclosure, a stacked array of five rotary and linear motors supports a robotic type manipulator that holds the head for adjustment. The setting of the degrees of freedom is made in relation to a master flexible disk containing adjustment data tracks, which in turn are decoded by complicated electronic circuits.